1. Field of the Invention
This invention relates to a screwless terminal for connecting a conductor with an electrical contact by means of a clamping spring that is operable between clamping engaged and disengaged positions by a manually operable slide member.
2. Brief Description of the Prior Art
The German patent No. DE 43 32 969 C1 discloses a screwless terminal wherein a conductor can be connected with a connection terminal. For this purpose, there is provided a resilient member that moves the connection terminal into a receiving position in order to insert the conductor into an opening of the connection terminal. In order firmly to clamp the conductor, one turns the tension member so that an eccentric segment on the tension member will release the connection terminal, whereby the conductor will be firmly retained on the connection terminal by the force of the spring. To release the conductor, the tension member must be turned again until the eccentric segment engages the connection terminal and until the clamping force of the connection terminal is overcome. This design of the connection terminal requires an operating tool, both for the purpose of firmly clamping and for removing an electrical conductor. Furthermore, the known connection terminal has an expensive construction because it is composed of many individual parts.
In the German patent No. DE 38 34 442 C2, a clamping device is disclosed wherein, in addition to the introduction opening for an electrical conductor, there is provided a slide device for the purpose of firmly clamping the conductor. To this end, there is provided between the electrical conductor and the slide a leaf spring that, upon introduction of the slide device, is compressed and thus firmly clamps the conductor. To separate the clamping connection, the slide is pulled out so that the leaf spring will spread and release the conductor. Of course, this clamping device offers the advantage that no tool is required to work the slide but, on the other hand, to remove the conductor, the slide must be pulled out and must then again be pushed into the housing for clamping action. The known clamping device furthermore entails the disadvantage that the leaf spring must be positioned rather laboriously in the housing and that the large number of individual parts makes the production of the clamping device laborious and expensive.
The present invention was developed to provide a connection terminal on which the conductor can be clamped in a simple manner without a tool and then can be removed again. Furthermore, the connection terminal should consist of a few individual parts and it should thus be possible to make it at reasonable cost.
Accordingly, a primary object of the present invention is to provide a screwless terminal connection that includes an electrical contact and a clamping spring arranged in a housing chamber that contains an opening for receiving the bare end of the conductor, a slide member being provided that is manually insertable against the restoring force of a spring to displace a resilient clamping leg to an inoperable position, whereby the conductor may be inserted into, or removed from, the connector chamber.
According to a more specific object of the invention, the slide element is movable from an initial released position toward an inserted position to engage or disengage the clamping connection between the conductor and the clamping spring. After activation, the slide element is returned to its initial position by means of a restoring spring. Thus, the slide element, as a rule, need be operated only for the unlocking process. Only in exceptional cases with thin, single-wire and fine-wire conductors must the slide element be operated in order to prevent damage to the fine-lead conductor as it is pushed in. After unlocking, the slide element then automatically returns to the starting position in which the conductor is firmly kept in place by the clamping spring. In the routine case, the operator of the connecting terminal always knows that the slide element is in the locked starting position and need be operated only for unlocking purposes. This offers the advantage that its clamping leg of the clamping spring is mechanically uncoupled from the resetting leg and thus decisively contributes to the safety of the xe2x80x9cconductor clampingxe2x80x9d and activation functions.
According to another object of the invention, the slide element can be shifted into the starting position by a part of the clamping spring. This design offers the advantage that the number of parts is reduced to a minimum because the clamping spring, on the one hand, takes over the function of the conductor connection and, on the other hand, does the job of fixing the activation element. The slide element can preferably be shifted along its longitudinal axis from the starting position into the unlocking position. On the slide element, there is preferably provided a catch that takes care of the activation of the spring leg earmarked for conductor connection. The slide element is preferably retained in the housing in a manner that it cannot be lost so that it cannot be lost inadvertently.
According to a preferred embodiment of the invention, the clamping spring has a spring leg that rests against the end of the slide element which is arranged in the housing. In this way, one can in a simple manner fix the slide element. For a particularly compact design, the clamping spring can between the clamping leg and the spring leg have a section of diminished width on which the slide element is run through. In that way, one can make the connection clamp with only minimal width.
Preferably, the slide element can be latched or arrested in the unlocked or released position. This enables the user to provide an open clamping point in order, for example, to insert a fine-lead conductor into the connection terminal which otherwise could be damaged by the clamping spring. A simple mechanical design of the latch device includes a latch element that engages a retaining recess contained in the connector housing. the latch member can be engaged and disengaged from the locking recess by simple rotation of a rotatably mounted end portion of the slide member.